The present invention provides methods for preparing migrastatin and a migrastatin analog by fermentation and migrastatin compounds useful in the treatment of disease conditions. The invention relates to the fields of chemistry, molecular biology, animal and human health sciences, and medicine.
Migrastatin is a polyketide that inhibits the migration or movement of cells. Migrastatin has therapeutic potential in the treatment of cancer, because migrastatin can be administered, alone or in combination with other anti-cancer drugs, to prevent metastases. Unfortunately, migrastatin is quite difficult to synthesize de novo, and strains that produce the compound have heretofore either not been available or have not been identified as producers of migrastatin. There remains a need for efficient means to produce migrastatin and migrastatin analogs. The present invention meets this need.
The present invention provides methods for making migrastatin, migrastatin analogs, and purified preparations of migrastatin and migrastatin analogs. The present invention also provides compositions containing migrastatin or migrastatin analogs useful in the treatment of cancer and other disease conditions in which the inhibition of cell migration is beneficial.
In a first embodiment, the present invention provides a method for making migrastatin and migrastatin analogs by fermentation of Streptomyces platensis. In a preferred embodiment, S. platensis strain NRRL 18993 is employed in the fermentation to produce migrastatin and migrastatin analogs.
In a second embodiment, the present invention provides a novel migrastatin analog.
In a third embodiment, the present invention provides methods for purifying migrastatin and migrastatin analogs.
In a fourth embodiment, the present invention provides pharmaceutical preparations comprising migrastatin and/or a migrastatin analog.
In a fifth embodiment, the present invention provides methods to treat cancer by administering a therapeutically effective amount of migrastatin or a migrastatin analog.
These and other embodiments, modes, and aspects of the invention are described in more detail in the following description, the examples, and claims set forth below.
Migrastatin is a polyketide that inhibits the migration or movement of cells. Migrastatin has therapeutic potential in the treatment of cancer, because migrastatin can be administered, alone or in combination with other anti-cancer drugs, to prevent metastases. Unfortunately, migrastatin is quite difficult to synthesize de novo, and strains that produce the compound have heretofore either not been available or have not been identified as producers of migrastatin.
The present invention provides methods for making migrastatin, migrastatin analogs, and purified preparations of migrastatin and migrastatin analogs. In a first embodiment, the present invention provides a method for making migrastatin and migrastatin analogs by fermentation of Streptomyces platensis. In a preferred embodiment, S. platensis strain NRRL 18993 is employed in the fermentation to produce migrastatin and migrastatin analogs.
Streptomyces platensis NRRL 18993 has previously been identified as a source of polyketide compounds known as dorrigocins. See U.S. Pat. Nos. 5,589,485 and 5,484,799, each of which is incorporated herein by reference. Prior to the present invention, it was not known that S. platensis produced migrastatin. Moreover, no migrastatin analogs have been described prior to the present invention. Surprisingly, when S. platensis NRRL 18993 is fermented in accordance with the protocol of Example 1, below, migrastatin and a migrastatin analog are produced together with the dorrigocins known to be produced in this strain.
Migrastatin and the migrastatin analog provided by the present invention can be isolated and purified from the fermentation broth by extraction and chromatography. Examples 1 and 2, below, describe the isolation and characterization of these compounds by LC/MS. Thus, the present invention provides isolated and purified preparations of migrastatin and a novel migrastatin analog.
The present invention also provides compositions containing migrastatin or migrastatin analogs useful in the treatment of cancer and other disease conditions in which the inhibition of cell migration is beneficial.
The compounds of the invention can be readily formulated to provide the pharmaceutical compositions of the invention. The pharmaceutical compositions of the invention can be used in the form of a pharmaceutical preparation, for example, in solid, semisolid, or liquid form. This preparation will contain one or more of the compounds of the invention as an active ingredient in admixture with an organic or inorganic carrier or excipient suitable for external, enteral, or parenteral application. The active ingredient may be compounded, for example, with the usual non-toxic, pharmaceutically acceptable carriers for tablets, pellets, capsules, suppositories, pessaries, solutions, emulsions, suspensions, and any other form suitable for use.
The carriers which can be used include water, glucose, lactose, gum acacia, gelatin, mannitol, starch paste, magnesium trisilicate, talc, corn starch, keratin, colloidal silica, potato starch, urea, and other carriers suitable for use in manufacturing preparations, in solid, semi-solid, or liquified form. In addition, auxiliary stabilizing, thickening, and coloring agents and perfumes may be used. For example, the compounds of the invention may be utilized with hydroxypropyl methylcellulose essentially as described in U.S. Pat. No. 4,916,138, incorporated herein by reference, or with a surfactant essentially as described in EPO patent publication No. 428,169, incorporated herein by reference.
Oral dosage forms may be prepared essentially as described by Hondo et al., 1987, Transplantation Proceedings XIX, Supp. 6:17-22, incorporated herein by reference. Dosage forms for external application may be prepared essentially as described in EP Pub. No. 423,714, incorporated herein by reference. The active compound is included in the pharmaceutical composition in an amount sufficient to produce the desired effect upon the disease process or condition.
For the treatment of conditions and diseases caused by infection, immune system disorder (or to suppress immune function), or cancer, a compound of the invention may be administered orally, topically, parenterally, by inhalation spray, or rectally in dosage unit formulations containing conventional non-toxic pharmaceutically acceptable carriers, adjuvant, and vehicles. The term parenteral, as used herein, includes subcutaneous injections, and intravenous, intrathecal, intramuscular, and intrasternal injection or infusion techniques.
Dosage levels of the compounds of the present invention are of the order from about 0.01 mg to about 100 mg per kilogram of body weight per day, preferably from about 0.1 mg to about 50 mg per kilogram of body weight per day. The dosage levels are useful in the treatment of the above-indicated conditions (from about 0.7 mg to about 3.5 mg per patient per day, assuming a 70 kg patient). In addition, the compounds of the present invention may be administered on an intermittent basis, i.e., at semi-weekly, weekly, semi-monthly, or monthly intervals.
The amount of active ingredient that may be combined with the carrier materials to produce a single dosage form will vary depending upon the host treated and the particular mode of administration. For example, a formulation intended for oral administration to humans may contain from 0.5 mg to 5 gm of active agent compounded with an appropriate and convenient amount of carrier material, which may vary from about 5 percent to about 95 percent of the total composition. Dosage unit forms will generally contain from about 0.5 mg to about 500 mg of active ingredient. For external administration, the compounds of the invention may be formulated within the range of, for example, 0.00001% to 60% by weight, preferably from 0.001% to 10% by weight, and most preferably from about 0.005% to 0.8% by weight.
It will be understood, however, that the specific dose level for any particlular patient will depend on a variety of factors. These factors include the activity of the specific compound employed; the age, body weight, general health, sex, and diet of the subject; the time and route of administration and the rate of excretion of the drug; whether a drug combination is employed in the treatment; and the severity of the particular disease or condition for which therapy is sought.
In another embodiment, the present invention provides a method of treating cancer, which method comprises administering a therapeutically effective amount of migrastatin, the novel migrastatin analog compound, or both, either alone or in combination with another anti-cancer compound.
The following examples are given for the purpose of illustrating the present invention and shall not be construed as being a limitation on the scope of the invention or claims.